Tornado: not making async request

Question

I'm a newbie to Tornado and I'm trying to use it to make an async call as in the documentation:

from tornado.httpclient import AsyncHTTPClient

def handle_response(response):
    """Handles response"""
    print 'here'
    if response.error:
        print "Error:", response.error
    else:
        print response.body

http_client = AsyncHTTPClient()
http_client.fetch("http://www.google.com/", handle_response)

When I run this program nothing is printed :(

The program just runs and exits. What am I doing wrong?

Answer 1

You have to start the IOLoop for asynchronous stuff to run. The last line of a tornado program is typically tornado.ioloop.IOLoop.current().start(). You'd then call IOLoop.current().stop() in handle_response, assuming this one request is all you want to do.

Another way to start and stop the IOLoop for a single function is like this: response = IOLoop.current().run_sync(functools.partial(http_client.fetch, url)) (and then you'd handle the response afterwards)